Paper #55 - ISHA Annual Scientific Meeting 2016

The Pathology of Hip Labrum and Chondrolabral Junction Varies with Radiographic Parameters

Shingo Hashimoto, MD, PhD, Kobe, Hyogo JAPAN
Shinya Hayashi, MD, PhD, Kobe JAPAN
Noriyuki Kanzaki, MD, PhD, Kobe JAPAN
Shinsuke Kihara, MD, Kobe, Hyogo JAPAN
Ryosuke Kuroda, MD, PhD, Kobe JAPAN

Kobe University Graduate School of Medicine, Kobe, Hyogo, JAPAN

FDA Status Not Applicable

Summary: The morphology of labrum tear and chondrolabral junction rupture is affected by mechanical environment of hip joint as well as age and gender of each case. It suggests that labrum tear due to FAI in young adults would have benefit with arthroscopic treatment, however labrum tear with hip instability in elder patients should be paid careful attention for the surgical indication.

Abstract:
Objectives
The causes for hip joint failure in young adult population are now described as labrum injury and articular cartilage damage in femoroacetabular impingement (FAI) and hip instability. Regarding the pathology of hip labrum and chondrolabral junction, it varies with mechanical variances and it may influence the outcome after arthroscopic surgery. Thus, in this study, we investigated the relationship between the pathology of hip labrum/ chondrolabral junction and anatomical variances, with evaluating radiographic parameters.

Methods
We examined 40 patients who were performed hip arthroscopic surgery for FAI and labrum tear in our institution. The hip labrum tear was classified as longitudinal tear, radial fibrillated tear, radial flap, and unstable, which were reported by Villar and collegues in 1996, during hip arthroscopy. In addition, the continuity of chondrolabral junction was also recorded, and the correlation with radiographic parameters was evaluated.

Results
Male patients was 13 and female was 27, and average age of total patients was 38.0 year-old. The number of patients in each labrum tear classification was 5 in longitudinal tear (mean age: 50.0), 17 in radial fibrillated tear (44.4), 11 in radial flap (30.6), and 7 in unstable labrum (19.3), and mean age and gender between groups were significantly different (p<0.001). The labrum tear morphology was significantly affected by some radiographic parameters: LCEA, ARO, alpha angle in lateral projection, and positive crossover sign (COS) (p<0.05). The mean degree of LCEA, hip instability parameters, was less than 25 degree in longitudinal tear, radial fibrillated and unstable group. The patients in longitudinal tear and radial fibrillated groups were relatively elder cases, and showed borderline dysplasia by smaller LCEA. The radial flap group showed normal coverage of acetabulum, larger alpha angle (mean 67.6 degree), and positive COS except one case. The unstable group included only younger females, and presented normal alpha angle (mean 44.6 degree) and no sign of arthritic change. When evaluating with the continuity of chondrolabral junction, the alpha angle was significantly different (p<0.05). The continuity was failure in cases with higher alpha angle. Clinical symptom (mHHS) after arthroscopic surgery was better in radial flap and unstable group than other (p<0.05), but no significant difference could be found when compared with the continuity of chondrolabral junction.

Discussion
The hip labrum morphology was affected by mechanical environment as well as age and gender of each patient. The longitudinal peripheral tear and/or radial fibrillated tear may be associated with hip instability and degenerative changes of hip joint. Unstable labrum was found in young female cases with hip instability. These findings suggested that hip instability introduce the unstable labrum, and it may proceed to radial fibrillated or longitudinal tear in elder age. On the other hand, radial flap tear was occurred in young higher activity male cases, which showed the radiographic features of cam and/or mixed type FAI, and this type showed better surgical outcomes with hip arthroscopy. Furthermore, clinical outcome in longitudinal and radial fibrillated tear was worse, so labrum tear due to FAI in young adults would have benefit with arthroscopic treatment, however labrum tear with hip instability in elder patients should be paid careful attention for the surgical indication.